title: Effective dose from direct and indirect digital panoramic units.
abstract: OBJECTIVE
  This study aimed to provide comparative measurements of the effective dose from direct and indirect digital panoramic units according to phantoms and exposure parameters.
  
  
  METHODS
  Dose measurements were carried out using a head phantom representing an average man (175 cm tall, 73.5 kg male) and a limbless whole body phantom representing an average woman (155 cm tall, 50 kg female). Lithium fluoride thermoluminescent dosimeter (TLD) chips were used for the dosimeter. Two direct and 2 indirect digital panoramic units were evaluated in this study. Effective doses were derived using 2007 International Commission on Radiological Protection (ICRP) recommendations.
  
  
  RESULTS
  The effective doses of the 4 digital panoramic units ranged between 8.9 µSv and 37.8 µSv. By using the head phantom, the effective doses from the direct digital panoramic units (37.8 µSv, 27.6 µSv) were higher than those from the indirect units (8.9 µSv, 15.9 µSv). The same panoramic unit showed the difference in effective doses according to the gender of the phantom, numbers and locations of TLDs, and kVp.
  
  
  CONCLUSIONS
  To reasonably assess the radiation risk from various dental radiographic units, the effective doses should be obtained with the same numbers and locations of TLDs, and with standard hospital exposure. After that, it is necessary to survey the effective doses from various dental radiographic units according to the gender with the corresponding phantom.
authors.affiliation: Department of Oral and Maxillofacial Radiology, School of Dentistry, Oral Biology Research Institute, Chosun University, Gwangju, Korea.
authors.forename: Gun-Sun
authors.initials: GS
authors.lastname: Lee
authors.forename: Jin-Soo
authors.initials: JS
authors.lastname: Kim
authors.forename: Yo-Seob
authors.initials: YS
authors.lastname: Seo
authors.forename: Jae-Duk
authors.initials: JD
authors.lastname: Kim
keywords: Radiation Dosage; Radiography, Dental, Digital; Radiography, Panoramic